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AssigneeDoosan Infracore Co., Ltd.
InventorsKi Hwan Jung, Dong Seob Shim, Sik Yang, Jae Hyoung Hwang
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The present disclosure relates to a flake graphite cast iron simultaneously having high strength, good machinability, and fluidity, to a method for manufacturing same, and to an engine body comprising the flake graphite cast iron for an internal combustion engine and, more particularly, to a method for manufacturing a flake graphite cast iron, for an engine cylinder block and head having improved castability, a low possibility of the occurrence of chill due to ferroalloy, stable tensile strength and yield strength, and good machinability by adding a trace of strontium in a cast iron including carbon (C), silicon (Si), manganese (Mn), sulfur (S), and phosphorus (P), which are five elements of the cast iron, molybdenum (Mo), a high strengthening additive, and copper (Cu) while controlling the ratio (S/Sr) of the sulfur (S) content to the strontium (Sr) content in the cast ion.
A method for manufacturing a high-strength flake graphite cast iron for an engine body, the method comprising:
A flake graphite cast iron for an engine body which consists of 3.2 to 3.5% of carbon (C), 1.9 to 2.3% of silicon (Si), 0.62 to 0.9% of manganese (Mn), 0.06 to 0.1% of sulfur (S), 0.06% or less of phosphorous (P), 0.6 to 0.8% of copper (Cu), 0.15 to 0.25% of molybdenum (Mo), 0.001 to 0.005% of strontium (Sr), and a remainder of iron (Fe) and other unavoidable impurities that satisfies 100% with respect to a total weight %, and simultaneously satisfies a chemical composition wherein a ratio (S/Sr) of the content of the sulfur (S) to the content of the strontium (Sr) is in a range of 16 to 98, wherein a chill depth of a wedge test piece is 3 mm or less.
Dependencies are inferred from the claim text.